Overview
The Watertight II is the kind of rain jacket I like for the unglamorous slot in a kit: cheap enough to actually bring, real enough to trust in normal weather.
Columbia gives it the useful basics: Omni-Tech waterproof-breathable fabric, full seam sealing, a breathable mesh lining, an attached adjustable storm hood, zippered hand pockets, adjustable cuffs, and a drawcord hem. It also packs into its own hand pocket, which matters because a rain shell left in the closet is not a rain shell.
This is not a premium alpine hardshell. It does not vent like a jacket with pit zips, and any 2-layer budget shell can feel clammy when you are hiking hard uphill. Where it shines is real-world shoulder-season use: wind at camp, surprise showers, travel days, wet trailheads, grocery runs in bad weather, and the "throw it in the back" layer you forget about until you need it.
Buy it for the boring job: staying dry enough, packing small, and not costing so much that you baby it.